1. Technical Field of the Invention
The present invention generally relates to Ethernet OAM networks. More particularly, and not by way of any limitation, the present invention is directed to a system and method for providing autoconfiguration of Ethernet OAM Maintenance Intermediate Point (MIP) nodes.
2. Description of Related Art
The link between the end user and the public network, essential key to the delivery of broadband applications to residential and business subscribers, is known by many names, e.g., first mile, last mile, local loop, metro access, subscriber access network, etc., and is implemented using a variety of different transport technologies and protocols over diverse physical connections. For instance, today most users connect to the public network with Digital Subscriber Line (DSL), Integrated Services Digital Network (ISDN), cable TV, T1/E1 or T3/E3 lines, using Synchronous Optical Network and its companion Synchronous Digital Hierarchy (SONET/SDH), Frame Relay and Asynchronous Transfer Mode (ATM). Regardless of the nomenclature or the actual implementation, all access networks require operations, administration and maintenance (OAM) support features to ensure the maintainability and uptime required to provide broadband services.
Current first/last mile solutions have significant shortcomings from the customer's perspective, ranging from performance bottlenecks, fixed bandwidth provisioning, limited scalability, lack of flexibility and provisioning complexity to end-to-end quality of service (QoS) issues and a high cost structure. The use of robust, simple Ethernet technology in the first mile promises to revolutionize the access network as it did the enterprise network. Ethernet is a local area network (LAN) transport technology that is used ubiquitously in the home and in business to communicate between computers and networks. As an access technology, Ethernet offers three significant advantages over legacy first mile technologies: (i) future-proof transport for data, video and voice applications; (ii) cost-effective infrastructure for data services; and (iii) simple, globally accepted standard that will ensure interoperability.
In order to adapt the Ethernet technology in a carrier-grade service environment, various standards are being developed that aim to provide advanced OAM capabilities (also referred to as Ethernet Connectivity and Fault Management or Ethernet CFM) across the entire network from one end to the other end. Since the end-to-end service network environment is typically comprised of a patchwork of diverse component networks (e.g., metro access networks and core networks using a variety of technologies) that may belong to different organizations, network operators and service providers, the Ethernet OAM plane is envisioned as a hierarchically layered domain space wherein specific OAM domains are defined corresponding to the constituent network infrastructure and provisioning. In particular, two standards, IEEE 802.1ag and ITU-T (Question 3, Study Group 13), incorporated by reference herein, that are specifically concerned with end-to-end Ethernet OAM define a customer-level domain at the highest level of hierarchy, which comprises one or more provider domains (occupying an intermediate level), each of which in turn includes one or more operator domains disposed at a lower hierarchical level. By way of standardization, the OAM domain space may be partitioned into up to a number of levels, e.g., 8 levels, each domain corresponding to a particular level, wherein a domain is defined in terms of what are referred to as flow points. In the context of the IEEE 802 specification suite, the flow points are new entities contained in Media Access Control (MAC) “interfaces” and “ports” as defined in related standards documentation. A port can implement multiple flow points, of different types. A flow point at the edge of an OAM domain is called a “Maintenance End Point” or MEP. A flow point inside a domain and visible to a MEP is called a “Maintenance Intermediate Point” or MIP Whereas MEP nodes are used by system administrators to initiate and monitor OAM activity (by issuing appropriate OAM frames), MIP nodes passively receive and respond to OAM flows initiated by MEP nodes.
An OAM domain having one or more MIP nodes is bounded by a pair of MEP nodes. In order that OAM frame flows are appropriately filtered so that they are processed only by the intended domain's nodes, the MEP/MIP population of an Ethernet OAM network needs to be properly configured. In accordance with the current standards, absolute OAM level encoding uses an integer value to indicate a specific domain level. Moreover, each MIP node at a given layer must be manually configured with its domain level in order to support proper OAM operation. Manual configuration can however be time-consuming as well as error-prone, particularly in a network with many levels and a large number of MIP nodes. If the MIP nodes are misconfigured for any reason with the wrong domain level, or if a MEP node is malfunctioning, security violations are possible due to leakage of OAM frames between domains.